50PK760 here it's a French version of the UK 790, which has the infinia design but lacks the true black filter of the PK990.
Got it from Pixmania as they ony seemed to sell the PK350 and 250 here in Ireland at the time and needed more HDMI ports and liked the all glass design.
So, I read this thread with great interest. I never really thought that the set lacked in black since I came from a m87 Samsung LCD from 2007.
I was hesitant to try this as I really was out of my depth. I was feeling sick to my stomach as I started to remove the back cover.
1. I was scared I would electrocute myself
2. Mess the tv up with my tinkering.
I just couldn't resist getting deeper blacks just by tweaking one little pot. All I ever was going to do was the set_up as I wasn't confident I would be able to put the pots back if I messed up.
Now, it took me around three hours because I had to do this myself. My wife was going to stand in front of the tv but my 15 month old decided that he was going to wake up eary. From his nap.
It also took me longer than I thought it would.
Set_up on my set was at 10 o'clock turning it clockwise to its stop produced many pix misfires on all my inputs.
Set_dn was at around 11 and turning it clockwise even a little produced misfires, so I left it at its default.
Vy was just under 12 o'clock turning it even a little also caused problems so left it at stock.
In the end I set set_up to 3 o'clock.
Every input had it's tolerances.
Sky+HD 1080i@50Hz had the largest headroom.
PS3 1080p@24Hz was second and the least tolerant was my Apple tv2 720p@60Hz.
Every time I thought I had it set I had to dial it back because of the Apple tv.
To be honest though I didnt notice any difference from full clockwise to where I have it in terms of the black level to my eye, of course I have no way of measuring the result but it looks the same to me anyway.
I did notice the glow in black fade as I dial set_up clockwise from its default, it was like a dimmer switch for black
I had contrast set to 80 before I did the tweek now I set it to 75.
I'm glad I did the because there is a difference but it was not without it's problems. I've noticed today that there are some pixel misfires(?) from black to a lighter scene, or in the menus on a no signal screen.
It's a few red pixels that take a few seconds to go away and sometimes they are blue or green or black, just a scattering of a few random pixels.
I can't see his from my normal viewing distance of around 8-9 feet.
No problems with a cold start so I'm going to leave it as is.